[aspell]: https://github.com/GNUAspell/aspell
[bs4]: https://beautiful-soup-4.readthedocs.io/en/latest/#
[build]: https://pypi.org/project/build/
[contains-draft]: https://www.w3.org/TR/2001/CR-css3-selectors-20011113/#content-selectors
[cssom]: https://drafts.csswg.org/cssom/#common-serializing-idioms
[custom-extensions-1]: https://drafts.csswg.org/css-extensions-1/
[html5lib]: https://github.com/html5lib/html5lib-python
[lxml]: https://github.com/lxml/lxml
[registry]: https://developer.mozilla.org/en-US/docs/Web/API/CustomElementRegistry